The present invention relates to a process for preparing liquid formulations of dyes of the general formula I 
where
Y is chlorine or bromine,
Z is hydrogen, chlorine, bromine, sulfonic ester, nitro or optionally substituted sulfamoyl, 
R is alkylene optionally interrupted by oxygen, 
m is 1 or 2,
n is 0 or 1,
p is 0, 1 or 2,
Anxe2x8ax96 is the equivalent of an anion,
R1 and R2 are independently hydrogen, optionally substituted alkyl, alkenyl, cycloalkyl, aralkyl or aryl or combine with the joining nitrogen to form a heterocycle,
R3 is hydrogen or optionally substituted alkyl,
B is hydrogen or C1- to C4-alkyl,
B1 is hydrogen, hydroxyl, C1- to C4-alkoxy or C1- to C4-alkyl, where
R4 is optionally substituted alkyl and
R5 is hydrogen or C1- to C4-alkyl, and the radical 
may also be an optionally substituted piperazine radical, by diazotizing an amine of the formula II 
and then coupling the diazonium salt onto a compound of the formula III 
and also optionally adding solubilizing additives.
Basic azo dyes of the general formula I are known from EP-A-0 162 409. Liquid formulations with desired counterions such as acetate are prepared by dissolving the interveningly isolated dye in the desired acid such as acetic acid. The intervening isolation is necessary to free the dye of unwanted salt. However, intervening isolations are costly and inconvenient from a processing viewpoint, since they require additional crystallization, suction filtration and washing of the dye.
It is an object of the present invention to provide a process leading to stable dye solutions which can be used directly, without intervening isolation, as liquid formulations or as a basis therefor. Costly and inconvenient isolating operations of the dye shall be avoided. Moreover, the liquid formulations shall be minimally corrosive, if at all, with regard to alloyed steels.
We have found that this object is achieved by effecting said diazotizing at a pH set to an acidic value using pure methanesulfonic acid or at least 20 mol %, preferably xe2x89xa750 mol % and especially xe2x89xa780 mol % mixtures of methanesulfonic acid in monobasic acids.
Pure methanesulfonic acid is to be understood as meaning using methanesulfonic acid as sole acidifying agent. Monobasic acids can be monobasic mineral acids or carboxylic acids, such as hydrochloric acid, hydrogen bromide, formic acid, acetic acid, hydroxyacetic acid, aminoacetic acid, methoxyacetic acid, propionic acid, lactic acid, benzoic acid, benzenesulfonic acid and toluenesulfonic acid.
It is preferable to set the pH for the diazotization to an acidic value using pure methanesulfonic acid or at least 20 mol %, preferably xe2x89xa750 mol % and especially xe2x89xa780 mol % mixtures of methanesulfonic acid in monobasic carboxylic acids.
Preference is given to formic acid, acetic acid, propionic acid and lactic acid in particular. The pH for the diazotization is preferably set using a mixture of methanesulfonic acid in formic acid.
The acidifying is preferably carried out in such a way that the diazotization pH is in the range from 0 to 3, more preferably in the range from 1.0 to 2.5 and especially 2.
Preferably, the acidifying is effected using methanesulfonic acid alone. In this case, methanesulfonic acid is preferably used in a molar ratio in the range from 2.5/1 to 3.5/1 based on 1 mol of amine II. A larger methanesulfonic acid excess leads to an increased salt content and therefore is undesirable. Particular preference is given to using 2.8-3 mol of methanesulfonic acid per mole of amine II.
In general, the amine II will be dissolved in the mixture of water and methanesulfonic acid. Solubilizing additives often used in liquid formulations can, if desired, already be present in the reaction mixture. Solubilizing additives are specified hereinbelow and are water-miscible organic solvents and also ureas and lactams. Preferably, no solubilizing additives are used. Instead, it is preferable to use water as sole solvent for diazotizing and coupling for dye I.
The diazotization is effected using customary diazotizing agents such as nitrous acid which is formed from an alkali metal nitrite at an acidic pH. Useful diazotizing agents further include nitrosylsulfuric acid and the neopentylglycol ester of nitrous acid.
After excess nitrite has been destroyed, with sulfamic acid for example, the compound III is added, generally as an aqueous solution. This coupling is preferably carried out in the pH range from 3 to 6 and more preferably from 4 to 4.5. The pH should not exceed 7, since otherwise the dye will start to crystallize. However, if the solubilizing additives specified hereinbelow are added, the stability with regard to crystallization is distinctly increased.
The coupling pH is set using agents known to one skilled in the art. Useful bases for this include for example sodium acetate, aqueous sodium hydroxide solution, sodium carbonate, sodium bicarbonate and amines such as ethanolamine.
The diazotization is effected in a conventional manner at from xe2x88x925 to 25xc2x0 C. To carry out the coupling reaction, the reaction mixture is allowed to warm and is if necessary heated to 30xc2x0 C. to complete the reaction.
The process is useful for preparing solutions of the dye of the general formula I.
Any alkyl and alkylene appearing in the abovementioned formula can be both straight-chain and branched. In substituted alkyl appearing in the abovementioned formula, possible substituents include for example hydroxyl and methoxy. The alkyl groups will then generally contain one or two substituents.
Useful anions Anxe2x8ax96 include for example monomethylsulfate, ethylsulfate, aminosulfonate, chloride, bromide, formate, acetate, hydroxyacetate, aminoacetate, methoxyacetate, propionate, lactate, benzoate, benzenesulfonate and toluenesulfonate.
Useful Z radicals in addition to those already mentioned include C1-C4 sulfonic esters whose alkyl radical is optionally substituted by mono- or di-(C1-C6)-alkylamino or morpholino, such as SO2OC2H4N(CH3)2, SO2OC2H4N(C2H5)2, SO2OC2H4N(C3H7)2, SO2OC2H4N(C4H9)2, SO2OC2H4N(CH2CH2)2O, SO2OCH(CH3)CH2N(CH3)2, SO2OCH(CH3)CH2N(C2H5)2, SO2OC4H8N(CH3)2 or SO2OC4H8N(C2H5)2.
Further examples of Z are sulfamoyl, phenylsulfamoyl or mono- or di-(C1-C4)-sulfamoyl, whose alkyl radicals are optionally substituted by hydroxyl or methoxy, such as methylsulfamoyl, mono- or dimethylsulfamoyl, mono- or diethylsulfamoyl, mono- or dipropylsulfamoyl, mono- or dibutylsulfamoyl, mono- or dihydroxyethylsulfamoyl or N-methyl-N-hydroxyethylsulfamoyl.
Alkylene R has for example from 2 to 10 carbon atoms and is optionally interrupted from 1 to 3 times by oxygen, xe2x80x94NR5xe2x80x94 or 
Specific examples are:
C2H4, C3H6, CH(CH3)xe2x80x94CH2, CH2xe2x80x94CH(CH3)xe2x80x94, C4H8, CH(C2H5)xe2x80x94CH2, C6H12, CH2xe2x80x94C(CH3)2xe2x80x94CH2, xe2x80x94C(CH3)2xe2x80x94CH2xe2x80x94C(CH3)2xe2x80x94, C2H4OC2H4, C3H6OC3H6, C3H6OC2H4OC3H6, C3H6OC4H8OC3H6, C3H6OC2H4OC2H4OC3H6, C2H4NHC2H4, C2H4NHC3H6, C3H6NHC3H6, C3H6NHC2H4NHC3H6, C3H6NHC6H12NHC3H6, 
R1 and R2 are independently for example C1-C14-alkyl, with or without hydroxyl, C1-C8-alkoxy, Nxe2x80x94C5-C8-cycloalkylamino, N,N-di-(C1-C4-alkyl)amino substitution, C2-C6-alkenyl or C5-C8-cycloalkyl.
Specific examples of R1 and R2 in addition to those already mentioned include: methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, n-amyl, i-amyl, n-hexyl, i-hexyl, heptyl, octyl, 2-ethylhexyl, decyl, dodecyl, tridecyl, tetradecyl, 2-hydroxyethyl, 2- or 3-hydroxypropyl, hydroxybutyl, allyl, methallyl, cyclopentyl, cyclohexyl or cyclooctyl, N,N-dimethylaminoethyl, N,N-diethylaminoethyl, N,N-dipropylaminoethyl, N,N-dibutylaminoethyl, 3-(N,N-dimethylamino)-propyl, 3-(N,N-diethylamino)-propyl, 3-(N,N-dipropylamino)-propyl or 3-(N,N-dibutylamino)-propyl, N-cyclohexylaminoethyl, 3-(N-cyclohexylamino)-propyl, 3-(N-cyclooctylamino)-propyl, N-methyl-N-cyclohexylaminoethyl, 3-(N-methyl-N-cyclohexylamino)-propyl, benzyl, phenethyl, phenyl or tolyl.
R1 and R2 can combine with the joining nitrogen to form for example the radicals of the following 5- or 6-membered heterocycles which optionally contain nitrogen or oxygen as a further heteroatom and are optionally substituted, such as pyrrolidine, piperidine, morpholine, piperazine with or without methyl, ethyl, n- and i-propyl, n-, i-, sec-butyl, 2-hydroxyethyl, 2-aminoethyl, 2- or 3-hydroxypropyl, 2- or 3-aminopropyl substitution on the nitrogen, imidazole with or without methyl, ethyl, propyl or butyl substitution in position 2 and/or 4, or N-3-(C1-C12)-alkyl- or vinylimidazole which may additionally be substituted by methyl, ethyl, propyl or butyl in position 2 and/or 4.
R3 and R4 are independently C1- to C12-alkyl which is optionally substituted by hydroxyl, C1-C4-alkoxy, chlorine or phenyl, such as methyl, ethyl, n- or i-propyl, n- or i-butyl, n- or i-amyl, n- or i-hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, 2-hydroxyethyl, 2- or 3-hydroxypropyl, hydroxybutyl, benzyl, CH2CH2(OH)CH2Cl or CH2CH(OH)CH2OH.
Examples of R5, B and B1 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl. B1 may further be for example methoxy, ethoxy, propoxy or butoxy.
The 
radical can also be a group of the formula 
The process is preferred in the case of dyes I in which Z is hydrogen, chlorine or bromine.
R1 and R2 are each preferably for example:
methyl, ethyl, n-propyl, i-propyl, C2- or C3-hydroxyalkyl or cyclohexyl. Preferred heterocyclic radicals formed by R1 and R2 together with the adjoining nitrogen are derived from morpholine, piperidine, 4-methylpiperazine, 4-ethylpiperazine, 4-hydroxyethylpiperazine, 4-(2xe2x80x2-aminoethyl)piperazine, imidazole, 2-methylimidazole or 4-methylimidazole.
The process is preferred for dyes I in which R3 is hydrogen, C1- to C4-alkyl, C2- to C4-hydroxyalkyl or benzyl, especially hydrogen, methyl, ethyl, hydroxyethyl or hydroxypropyl.
It is further preferred for dyes I in which R4 is methyl, ethyl or hydroxyethyl. It is further preferred in the case of dyes I in which B and B1 are independently selected from the group consisting of hydrogen and methyl.
The process is particularly useful for preparing compounds of the formula IV 
where R, R1, R2, R3, n, m and y are each as defined above.
The process is particularly preferred for dyes IV in which Y is hydrogen or nitro and/or R is ethylene, propylene, isopropylene or butylene.
It is further preferred for dyes IV in which R1 and R2 are each hydrogen, methyl, ethyl, n- or isopropyl, n-, iso- or sec-butyl, methoxyethyl, cyclohexyl or combine with the joining nitrogen atom to form morpholinyl, piperidinyl, piperazinyl, N-methylpiperazinyl, N-ethylpiperazinyl or imidazolyl and R3 is hydrogen, methyl, ethyl or hydroxyethyl.
The process according to the invention provides dye solutions which can be further used directly for liquid brands. The dyes are very soluble, so that they give stable liquid formulations. This method obviates costly and inconvenient isolating operations on the dye as well as additional purifying steps which give rise to wastewater. Furthermore, the liquid formulations obtained are only minimally corrosive with regard to alloyed steels, if at all.
If desired, the dye solutions are admixed with solubilizing additives. Such additives include for example water-miscible organic solvents such as C1-C4-alkanols, for example methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol or tert-butanol, carboxamides, such as N,N-dimethylformamide or N,N-dimethylacetamide, ketones or ketoalcohols, such as acetone, methyl ethyl ketone or 2-methyl-2-hydroxypentan-4-one, ethers, such as tetrahydrofuran or dioxane, mono-, oligo- or polyalkylene glycols or thioglycols having C2-C6-alkylene units, such as ethylene glycol, 1,2- or 1,3-propylene glycol, 1,2- or 1,4-butylene glycol, hexane-1,6-diol, diethylene glycol, triethylene glycol, dipropylene glycol, thiodiglycol, polyethylene glycol or polypropylene glycol, other polyols, such as glycerol or 1,2,6-hexanetriol, C1-C4-alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyldiglycol) or triethylene glycol monomethyl ether or triethylene glycol monoethyl ether, C1-C4-alkyl esters of polyhydric alcohols, xcex3-butyrolactone or dimethyl sulfoxide. Suitable solubilizing additives further include lactams, such as xcex5-caprolactam, 2-pyrrolidinone or N-methylpyrrolidin-2-one, urea, cyclic ureas, such as 1,3-dimethylimidazolidin-2-one or 1,3-dimethylhexahydropyrimid-2-one.
Preferred solubilizing additives are ureas, caprolactam, mono-, di- or trialkylene glycols having C2-C4-alkylene units and also oligo- and polyalkylene glycols having ethylene and/or propylene units and also their C1-C4-alkyl ethers and C1-C4-alkyl esters. Very particular preference is given to ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, butyldiglycol, ureas and caprolactam.
Preferred liquid brands contain essentially
15-30% by weight of dyes I (based on the dye without counterion)
0-30% by weight of solubilizing additives
based on the total amount of the aqueous liquid brand. Preference is given especially to liquid brands which contain no solubilizing additives. The liquid brands are useful, inter alia, for dyeing and printing cellulosic fiber materials such as wood-containing and wood-free paper materials.